2016 Mercruiser 6.2 ECT - long beep every few minutes???

[tpenfield]

Here are the screen shots of the port engine. . .
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Same thing, slightly different. You would think it would show the battery voltage the same or higher than the 12 volt 'system' voltage.

 

[alldodge]

STBD 12.8 and 11.5
PORT 12.9 and 11.9

What is the Diff at the Port Engine?

 

[tpenfield]

This might be what is confusing the VesselView . . .

Starboard engine 'sees' the battery voltage as 1.3 volts lower than the system voltage.

On the port engine it is 1.0 volts. Maybe 1.3 volts difference crosses a threshold.

 

[tpenfield]

STBD 12.8 and 11.5
PORT 12.9 and 11.9

What is the Diff at the Port Engine?

The port engine does not seem to mind the voltage difference . . . so maybe 1.0 volts is OK and 1.3 is not.

 

[alldodge]

Maybe you already posted it, but what does the Port engine show with Diacom connected at the Port engine like you did with Stbd?

 

[nola mike]

Also noticed that on the engine data ignition voltage is > battery voltage?

 

[tpenfield]

Maybe you already posted it, but what does the Port engine show with Diacom connected at the Port engine like you did with Stbd?

Post #81.

 

[tpenfield]

I've come across a few forum posts on various site, both marine and automotive regarding the voltage discrepancy, but no absolute solution.

Clearly nothing can be higher than the battery voltage with the ignition on and the engine not running. And nothing can be higher than the alternator voltage while the engine is running. So, it must be an issue in how the PCM is getting/sensing 'battery voltage'. I think I will check the connections to the PCM to see if the pins are getting corroded, etc.

 

[alldodge]

My heads starting to hurt
port 81 - motor is running
stbd 78 - motor in not running

I'm trying to compare apples only

 

[tpenfield]

My heads starting to hurt
port 81 - motor is running
stbd 78 - motor in not running

I'm trying to compare apples only

I may have some more screen shots that are apples-to-apples.

 

[tpenfield]

Starboard engine running . . .

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voltage difference is 1.1

 

[alldodge]

Oh well, just blew that one
STBD 13.1 and 12.0 problem child low voltage
PORT 12.9 and 11.9

STBD has misfires 1, 2, 8
CAT temp 200* higher
Less fuel ms and more degree timing
Idle set 600 Port idle set 636

That's all I got, hope @muc might see something

 

[Scott Danforth]

Looking at screenshots in different posts is like looking for waldo when you are drunk

 

[alldodge]

Looking at screenshots in different posts is like looking for waldo when you are drunk

Yep, I brought up the thread in 3 windows. Port, Stbd and my comments

 

[tpenfield]

My eyes glossed over just looking at the computer screens - more data than I can digest.

I did not notice the voltage discrepancy- so thanks @alldodge for pointing that out.

 

[tpenfield]

Thoughts for today . . . I got to go to the dentist (looking for a volunteer to go in my place ) Before that, I'll spend some more time out at the boat with computer in hand.

I found some information (tech manual) on the PCM112 controller, and noticed that there is a battery reference wire, which is Pin A4 on the C-Pocket connector. Other voltage sources are on Pins E4, F1 & 2.


The Battery reference wire has a 2 amp fuse in series. So, I will try to see if the voltage at the pin is lower than the battery voltage, meaning a voltage drop across the wiring or fuse. There are some 2 amp fuses on the engine, along with other fuses.

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We shall see how that goes. In my Internet searching, I've come across some folks saying that replacing a fuse corrected a low voltage warning. . . maybe it is the 2 amp fuse.

A small amount of resistance (5-10 Ohms) potentially could drop the voltage by the 1-2 volts that I am seeing (If the PCM is measuring voltage correctly).

Then it will be off to the dentist . . . followed by the knee joint therapist.

 

[Lou C]

Wonder if there could be some oxidation on that fuse….might be solved by just removing and reinstalling…
That boat was from Long Island & in our salt environment these issues are not uncommon. One year at spring start up I had no cranking power, no gauges with ignition on. The old school glass fuse had continuity but the metal ends were oxidized! Replaced all those old fuses & all back to normal.

 

[tpenfield]

Quick Update . . .

The voltage at pin A4 of the 'C' pocket connector is exactly the same as the battery. 12.87 volts

I removed and cleaned the 2 amp fuse. The resistance of the fuse was negligible - same as a short circuit.

I Powered the engine back up and ran it . . . still is getting the critical voltage warning.

I have a couple of Rinda Diacom screen shots - Stbd engine not running, and running. Also the VesselView settings and warning history

Something seems to be dragging down the voltage on both engines - the starboard being the worse, or the PCM's are not reading the battery voltage properly. Port engine reads about 1.0 volts low . . . Starboard engine reads about 1.3 volts low and sets off critical warning.

You can see that I set the lower warning limit to 10.7 volts, it still gives an alarm. I am wondering if it is because of the prior warnings that may need to be 'cleared/deleted' . . . just not sure how to do that on the vessel view.

PCM's show no codes.

PCM and VesselView do not seem to be 'on the same page' (or singing from same sheet of music ) . I would think the PCM would be filing a complaint about the voltage, but it is not.
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I may swap the batteries to see if it is a 'weak' battery.

TIA for any input, or thoughts on this.

 

[Lou C]

If you can access the main + stud on the fuse box, what’s the voltage there? Any drop between the bat switch & fuse box?
How’s the fuse box negative to battery connection?
I found a high resistance circuit in my old wiring harness by measuring both then running jumper wires to figure out which side (+ or -) the problem was on… Instead of pulling apart the old harness I ran a supplemental feed to the + side where the drop was and after that everything worked better….

 

[tpenfield]

You bring up a good point @Lou C The ground lead for the battery voltage ground pin at the PCM could have a bad connection . . . I'll see about checking that as well.